A typical flow control valve today consists of a direct drive spool valve used to vary a controlled flow area and an additional spool valve which senses the flow pressure drop across the first valve and restricts or relieves flow in order to maintain a constant flow to a work port regardless of the required working pressure.
It is an object of the invention to provide a low flow, easily assembled, low cost flow control valve that enables the aforementioned valve to be replaced with the valve embodying the invention.
It is a further object of the invention to provide a direct drive spool valve that incorporates both functions into one spool, that is, both the controlled flow area and the restricting and relieving area functions are controlled simultaneously to maintain constant flow.